Modern brake systems exert braking force on the wheels of a vehicle through electrical actuation, at least in some operating states. In certain operating states this braking force is greater than and independent of the driver's command. Such a, brake system, is then electrohydraulic brake system described in W. Jonner et al., "Electrohydraulic Brake System--The First Approach to Brake-By-Wire Technology," Society of Automotive Engineers, Paper No. 960991, 1996, pp. 105-12. In this brake system, electrical control signals are formed for the hydraulic actuators assigned to the individual wheel brakes as a function of the driver's intent detected by electrical means, or a brake system with traction control or vehicle dynamics control, in which, under certain conditions, an automatic braking sequence is initiated and braking force is built up on the wheel brakes independently of the brake pedal actuation by the driver (e.g., German Patent No. 195 24 939). A hill holder function, in which, under certain predefined operating conditions, braking force is also applied independently of the driver, can be considered an extension of such a brake system. Furthermore, electropneumatic brake systems and brake systems with electromechanical brake application are known.
With such brake systems, satisfactory control of the braking sequence, its limit ranges and/or satisfactory stabilization of the vehicle, is achieved. At standstill, the vehicle is held by the brake actuated by the driver (except for vehicles with hill holder). The braking force needed for standstill is usually less than that applied during the braking sequence, since no kinetic energy needs to be counteracted. Holding compensation is only required the force driving the vehicle down a, slope. Thus, in a collision accident, in particular at standstill and from behind, the vehicle can be displaced despite brake actuation. This is critical, especially when the vehicle is pushed into a danger zone (for example, when stopping for a traffic light at a crossing).